Previously, industrial robots having teaching and playback which could be flexibly set in response to the desired type of work by changing the operational programs thereof were used as automatic machines which performed work such as painting or welding in place of human beings.
This type of industrial robot comprises a robot body which moves and operates work tools attached thereto and a control apparatus which controls the movement of the robot body and the work tools. In addition, the automatic control exercised by this control apparatus is carried out based on an operational program stored in tile control apparatus, which is created by the teaching operation.
Furthermore, the data for the switching of the operation state of the work tool (for example, if the work tool is a paint gun, the data on whether or not paint is sprayed) are established, in the case of a PTP (point-to-point) teaching method, for each teaching point as the data in the operation program at the time of the instructed operation.
For example, as shown in FIG. 1, the form of the data of a conventional operation program at the time when a spray gun 1 attached to a robot body 2 carries out the painting operation shown by path 4 with respect to work 3 is in the form shown in FIG. 6. That is to say, position data 5, which show the posture of the robot body at each point of teaching, transfer data 7, which show the transfer state to the next teaching point (the transfer speed, etc.), and movement data 6 of the work tool (for example, a spray gun) are established for each teaching point, and memory area is secured for the movement data 6 of the work tools at each teaching point as well.
Furthermore, in this case the teaching operation is carried out by the successive storing of the characteristic points of the operational path by the operator. That is to say, the robot body 2 is operated manually, and point P1 is first instructed. Next, point S1, at which painting begins (spray gun is turned on), point S2, at which painting stops (spray gun is turned off), points P2 and P3, at which the path changes, points S3 and S4, at which the painting is turned on and off, point P4, at which the path changes, etc., which indicate the posture of the robot and the state of operation of the spray gun (that is, operation data 6), are instructed, and the operation program thus created.
In addition, in the same way, in the case of CP (continuous path) teaching, there is no establishment of data concerning the transfer between teaching points as shown in FIG. 5; however, robot body positional data 15 and work tool operation data 16 are stored at regular time intervals for each teaching point.
When the operational program data created in the above manner are viewed from the standpoint of the movement of the robot body, it is sufficient for the positional data 5 and the transfer data 7 if teaching points P1, P2, P3, and P4 are included, while points S1, S2, S3, and S4 are unnecessary. Furthermore, when they are viewed from the standpoint of the operation of the work tool, it is sufficient for operation data 6 if teaching points S1, S2, S3, and S4 are included, while teaching points P1, P2, P3, and P4 are unnecessary. In this way, there are many superfluous parts in the stored teaching program in the conventional method of control, and the memory efficiency is poor. In addition, as the posture of the robot body and the operation state of the work tool must be instructed for each teaching point, there are times in the teaching operation when there are many complications.